It doesn't really make sense for spectrum to design a blowing nugget(system studio) to be used with their flat glass line, and then make a better blowing glass(system premium) not deigned to be used with their flat glass, yet to have the flat glass coe closer to the better glass.

If the flat was a true 96, then nearly everyone using cullet, including Charles, should be able to use it. Not to mention most of the people using spruce.

I've had 0 problems with the studio nuggets and the flat glass. I've gotten away with the premium and flat sometimes, but there were colors that wouldn't take.